Patent GB-476844-A (GB)
Title: Improvements in machine tools particularly honing and lapping machines
IPC: B24B33/02
Filed: 1937-01-29
Abstract: 476,844. Honing and lapping cylinders. BURGESS, A. F. (Barnes Drill Co.) Jan. 9, 1937, No. 2672. [Class 60] A machine for honing and lapping the internal surface of long cylinders, for example the recoil and recuperator cylinders employed in gun carriages, comprises means for reciprocating the hone without rotation, but with periodic indexing, within the cylindrical bore and also for reciprocating and rotating the hone. The machine comprises a base section 14 carrying supports 15 for the work 16 and means 18, 20 for supplying cooling liquid to the work from a pump 21. in the base 14, which also contains a filter &c., 23 and a reservoir 24. A base section 13 is provided having thereon ways 27 on which is reciprocated a carriage 25 having a tool spindle 26, driven through gearing 30a, 31a, from a shaft 32. The carriage is reciprocated by means of cables 37 attached to the carriage and wound round a drum 33 driven by a reversible fluid motor 35 ; the cable also passes round a flexibly mounted sheave 38, and the motor is driven by a pump 39 driven by an electric motor 40. The spindle 26 is driven continuously or intermittently, the continuous drive being from an electric motor 44 through gears 46 ... 49 to a terminal gear 50 with which may be engaged a gear 57 on a connecting element 45 splined to the shaft 32 thereby to drive the shaft. In order to impart an intermittent rotation or indexing motion to the tool spindle, the member 45 is moved along the shaft 32 so as to disengage the gears 57, 50 and to bring teeth 45a on the end of the member into engagement with teeth on a sleeve 68 rotatable on the shaft 32 and having thereon a ratchet-wheel 67 engaged by pawls 69, 70 carried by gear wheels 63, 64 which are rotated by a rack 60. The rack 60 is reciprocated by a piston 61 in a cylinder 62 connected at its ends to the motor 35 and arranged so that as the fluid flow to the motor is reversed, so it is to the cylinder ; the tool spindle is therefore indexed at each reversal of the motor. The member 45 is moved by a lever 78, which may be set in a neutral position or to give either the continuous or the indexing drive to the spindle 26. In order to avoid abrasive marks on the work the indexing of the spindle 26 is arranged to be non-uniform by providing teeth of unequal lengths on the ratchet-wheel 67 ; the indexing may be arranged to take place only on alternate strokes of the tool carriage by putting either pawl 69, 70 out of action by means of a sliding cam, which lifts the pawl clear of the ratchet-wheel. The machine has control means thereon including a manual lever 86 pivoted at 87 to a flange 88 on a sleeve 89 rotatable on a bearing in the frame 13; movement of the lever about the pivot 87 moves a plunger to control the starting and stopping switches 91, 92 of the motor 44, and rotational movement of the sleeve 89 moves a link 95, which through bell crank lever 96 and link 98 opens or closes a control valve 99 in the fluid supply to the motor 35. The motor 35 is reversed by mechanism comprising a slidable rod 101 carrying stops 102, 103 to define the extreme. limits of stroke of the spindle carriage, and a stop 104, which with the stop 102 defines the working stroke. The stops are moved by a lug 105 on the carriage and the rod moves a cam block 106 which operates a reversing- valve 108 which, in conjunction with a hydraulically operated reversing-valve 109, reverses the supply of fluid to the motor 35. An automatic control device also is provided including means for counting the reciprocations of the tool and automatically, after a given number of strokes, stopping the machine. This operation is brought about by means of an auxiliary control-rod 110 carrying a stop 111 which normally lies out of the path of the lug 105, but which, when the rod 110 is turned, is engaged by the lug, so that the rod is moved axially against the pressure of a spring 118. The stop 111 has an arm 112 extending downwards so as to engage a stud 113 on the flange 88 of the sleeve 89 whereby, on movement of the rod, the sleeve is rotated to stop the reciprocation of the carriage 25. The rod 110 is rocked to operate as described above, by a solenoid 121 a link, and an arm on the rod, a switch 121a in the solenoid circuit being closed after the predetermined number of strokes by the counter 122 which has an arm 122b engaged by the cam plate 106 as this reciprocates with the rod 101 ; a switch 124 also is actuated to open the circuit of the spindle motor 44, and the counter is reset, and the switch 124 operated by a bar 125 movable with the rod 110. The rod 110 is rocked to normal position by spring plungers acting on arms projecting from a collar on the rod; the rod 110 may be rotated manually by a lever 110a and the rod 101 may be rotated, to move the stop 104 out of the path of the lug 105, by a lever 106a. The tool when withdrawn from the work is supported by a rest 132 which also serves to guide the tool into and out of operating position, the rest comprising a semicylindrical cradle adjustable by inclined ways 138 and screws 139 on a base 133 movable on the base 14 by a rack and pinion. The electrical supply to the motors 44 and 21 is controlled by a switch 140 operated by a solenoid 143, the circuit of which is controlled by the switch 91, and the holding circuit of which also includes the switches 92, 124; a shunt brake 44a may be provided to stop motor 44 quickly. The motor 40 is controlled by a switch 147 in the circuit of a solenoid 146, and the holding circuit includes a switch 149. Fluid for operating the reversing valve 109 is provided by a high pressure pump discharging through the reversing-valve to the ends of the cylinder of valve 109, and fluid for operating the motor 35 and piston 61, is supplied by a low pressure pump 39, the flow of fluid being controlled by the piston 155 of valve 109 for reversing the motor and by the valve 99 for stopping the motor. In operation, the work may be honed with the tool rotating and reciprocating until, after a given number of strokes, the tool is withdrawn from the work, after which hone is replaced by a lapping-tool and the work lapped with the tool not rotating, but indexed for a given number of strokes.